How good is Focus rust protection

I declined the dealer-offered rust treatment program when I bought the car 3 winters ago, and have had it oil-sprayed annually. It looks like new. I have no idea what it would look like if I had not had it sprayed.

Being raised in the salt belt (Ontario, Canada) I was quite surprised to see the underside of my new Focus wagon when I picked it up (here in Switzerland). I'm not used to seeing bare painted metal under a car. At least here, the Focus has undercoating only on the sides of the underbody, where stones would hit. The whole centre tunnel and parts of the wheelwells are not coated. The idea that all cars must have textured undercoating is burned in my head like one of the ten commandments. However, my friend's Audi has had a deep key scratch (to the metal) for five years now with no problem (he didn't paint over it), so galvanized steel does work. There is a bare, unpainted Porsche 911 chassis sitting outside the Porsche plant for more than 20 years now with no rust (the P911 was one of the first fully galvanized production cars). Still, it looks strange to see everything so "naked" under the car.

Stephen